A multidisciplinary group of investigators with expertise in comparative medicine, pathology atherosclerosis, biochemistry, lipid metabolism, and neutrophil and platelet function will seek answers to pertinent questions about the effect of dietary fish oil on plama lipids, platelet and neutrophil lipid composition and function, and atherosclerosis in Cercopithecus acethiops (vervets). Animals with or without 1 clip 2 kidney hypertension will be fed diets with or without fish oil in a 2 x 2 factorial experiment. Platelet aggregation and platelet survival will be measured. The effect of incorporation of eicosapentaenoic acid into cell membranes on the products of cyclooxygenase and lipoxygenase pathways will be studied in platelets and neutrophils along with effects on production of prostacyclin by the artery. These effects will be compared to those of the products of arachidonic acid. The animals will be fed the experimental diets for 3 years. The long-term effects of fish oil either beneficial or adverse will be assessed, and the amount of atherosclerosis determined morphometrically. Short-term studies and epidemiologic studies suggest that fish oil should have a beneficial effect on cordiovascular disease. Our long-term objectives are to clarify the mechanisms of any beneficial or adverse effects and to determine the optimum level of dietary fish oil to obtain the greatest benefit with least adverse effect.